Book Image

Learning Go Programming

Book Image

Learning Go Programming

Overview of this book

The Go programming language has firmly established itself as a favorite for building complex and scalable system applications. Go offers a direct and practical approach to programming that let programmers write correct and predictable code using concurrency idioms and a full-featured standard library. This is a step-by-step, practical guide full of real world examples to help you get started with Go in no time at all. We start off by understanding the fundamentals of Go, followed by a detailed description of the Go data types, program structures and Maps. After this, you learn how to use Go concurrency idioms to avoid pitfalls and create programs that are exact in expected behavior. Next, you will be familiarized with the tools and libraries that are available in Go for writing and exercising tests, benchmarking, and code coverage. Finally, you will be able to utilize some of the most important features of GO such as, Network Programming and OS integration to build efficient applications. All the concepts are explained in a crisp and concise manner and by the end of this book; you would be able to create highly efficient programs that you can deploy over cloud.
Table of Contents (18 chapters)
Learning Go Programming
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface

Package visibility


Regardless of the number of source files declared to be part of a package, all source code elements (types, variables, constants, and functions), declared at a package level, share a common scope. Therefore, the compiler will not allow an element identifier to be re-declared more than once in the entire package. Let us use the following code snippets to illustrate this point, assuming both source files are part of the same package $GOPATH/src/foo:

package foo   
   
var (   
  bar int = 12   
)   
   
func qux () {   
  bar += bar   
}   

foo/file1.go

package foo   
   
var bar struct{   
  x, y int   
}   
   
func quux() {   
  bar = bar * bar   
}   

foo/file2.go

Illegal variable identifier re-declaration

Although they are in two separate files, the declaration of variables with identifier bar is illegal in Go. Since the files are part of the same package, both identifiers have...